convert emoji short name to image using custom function

Question

I have created a function that converts emoji short name to image but I am stuck how do i get emojis short names from a string so the function can convert those to emoji image .

$field_from_db  = ':slight_smile:';
$shortcode_replace = shortcode_replace();
$shortname = $shortcode_replace[$field_from_db]; This code search in shortcode fucntion and replaces it with unicode to get cdn image 
$shortname = $shortname[0];


echo convertImage($shortname); after we got unicode for cdn predesigned in the shortcodes function it returns back with the image url 

Now i am confuse how it will convert from a string

$field_from_db  = 'Hello How are you :slight_smile::joy:';
//Here we have a string so how do i convert all short names to emoji using the function i created 

Answer 1

A simple solution is to use preg_match_all function to return the short names from string and iterate through each of them to convert into image.

<?php

$string  = 'Hello How are you :slight_smile::joy:';

$regex = "/:([a-zA-Z0-9_]*):/";
preg_match_all($regex, $string, $matches);

print_r($matches[0]);

Demo: https://3v4l.org/ro1m3

Hope it helps!

Answer 2

Depending on the format of the short names that you store, you could for example start the match with 1 or more a characters a-z or digits using a case insensitive pattern.

Then optionally repeat a single character from for examople a character class [-’_] followed by again 1 or more a characters a-z or digits.

:[a-z0-9]+(?:[-’_][a-z0-9]+)*:

Regex demo | Php demo

For a bit broader match, you could match 1 or more non whitespace characters excluding a colon, between to colons:

:[^:\s]+:

Regex demo

Example:

$field_from_db  = 'Hello How are you :slight_smile::joy::_do_not_match:test test::';
$regex = '/:[a-z0-9]+(?:[-’_][a-z0-9]+)*:/i';
preg_match_all($regex, $field_from_db, $matches);
var_export($matches[0]);

Output

array (
  0 => ':slight_smile:',
  1 => ':joy:',
)